The present invention relates to an optical finder system employed in a camera, and more specifically to a real image optical finder system in a camera having an LCD display panel for displaying information superimposed on an image seen in the finder.
In a real image type optical finder an image of an object is formed on an imaging plane by an objective lens group. Then this image is viewed by a user using an eyepiece lens group. In order for information shown on the LCD display to be viewed, the LCD display must be located in a plane coincident with the image plane.
The information displayed on the LCD panel will be superimposed on the image seen in the finder and may include alphanumeric characters. Further, lines or symbols which delimit an area of the image that is used by a distance measuring device to determine a distance of an object from the camera, may also be displayed.
Recently, zoom compact cameras have been introduced which employ the above mentioned real image optical finder system. In these cameras, the finder also includes a moving lens group, which is used to vary a magnification of an image seen in the finder in accordance with a focal length of the photographing lens. The information displayed on the LCD display can be changed as the focal length is changed.
The LCD display consists of an LCD panel and a polarizer disposed on either side of the LCD panel and close to the LCD panel. With this construction, there are six surfaces associated with the LCD display that are located very close to the image plane. During manufacturing of the camera and with normal use of the camera, dust particles which may enter the finder system can adhere to the six surfaces. The dust particles are therefore visible to the viewer resulting in an undesirable image being seen through the finder.
One method of reducing the number of surfaces near the image plane has been to move the polarizers sufficiently far away from the LCD panel so that they are out of focus. However, with this construction, the size of the finder becomes large, making it difficult to reduce the size of the camera.